This invention relates to flasks or containers and systems used for aerobic fermentation used to cultivate the aerobic growth of microorganisms, cell lines or other biological organisms.
For a variety of biotechnology applications there is a need to take a few biological organisms and as quickly as possible, multiply or grow them into significantly larger numbers of organisms. The biological growth usually increases with the oxygen level.
One common method of cultivating biological organisms is to place them in a flask in a liquid medium, and then oscillate the flask at a predetermined rate in an enclosed incubator. This approach can use a flask disclosed in a patent to Tunac, U.S. Pat. No. 4,665,035, which flask uses specific patterns of baffles on the bottom and neck of the flask. But Tunac's use of these baffles, including the internal baffles to inhibit the fluid from splashing out of the flask, has significant disadvantages. The cost of making the Tunac flasks is high enough that they must be reused. Unfortunately, reuse requires cleaning the flasks and filters in an autoclave and despite such cleaning it is not uncommon to have sufficient contaminants remain that reuse of the flask contaminates the samples cultivated in the reused flask. There is thus a need for an efficient flask that overcomes these deficiencies.
Further, the goal of cultivation is to produce as large an increase in the biological organisms as possible in as little time as possible. The use of the prior art containers, such as Tunac, often produce inconsistent growth rates, in part due to residual contamination arising from reuse. There is thus a need for a container that produces an increased growth rate of the biological organisms, consistently, and preferably while reducing the risk of contamination.
The prior art containers allow air to enter the container, and many containers filter the air. For example, Tunac describes a complex ribbed cap and filter to help diffuse oxygen in the flask. But the cap and filter in Tunic's container are expensive to make, and are thus reused, resulting in a risk of contamination and high operating costs. There is thus a need for an improved cap design.
The prior art containers have openings at the top of the containers and laboratory personnel often insert pipettes through these openings to gather samples and add contents from the containers at various stages of cultivating the biological organisms in the containers. As the containers become larger longer pipettes are needed, and laboratory personnel sometimes tilt the containers and spill everything out in using the pipettes. Further, removing and reattaching the caps to access the containers sometimes contaminates the caps. There is thus a need for an improved way to allow sampling of and addition to the contents of the containers while reducing contamination.